Herbicidal 1,2-dihydroquinolines and 1,2,3,4-tetrahydroquinolines



United States Patent 3,539,578 HERBICIDAL 1,2-DIHYDROQUINOLINES AND 1,2,3,4-TETRAHYDROQUINOLINES Joseph Patrick Brown, Llangollen, Wales, assignor to Monsanto Chemicals Limited, London, England, a British company No Drawing. Original application Aug. 18, 1965, Ser. No. 480,756. Divided and this application Mar. 27, 1968, Ser. No. 739,573 Claims priority, application Great Britain, Aug. 25, 1964, 34,669/ 64 Int. Cl. C07d 33/46 US. Cl. 260-287 9 Claims ABSTRACT OF THE DISCLOSURE 1-acyl-2-2,4-trialkyl-8-substituted hydroquinolines in which the substituent in the 8 position is alkyl or alkoxy having from 1 through 4 carbon atoms, or phenyl-derivative aromatic or aroxy. These compounds have utility as herbicides.

This application is a division of applicants copending application Ser. No. 480,756 filed Aug. 18, 1965, and now abandoned.

This invention relates to new hydroquinolines useful as herbicides. More specifically, it relates to novel hydroquinolines wherein the nitrogen atom of the quinoline ring has an acyl substituent. While the preferred compounds of this invention are 1,2-dihydroquinolines, other dihydroquinolines, such as 3,4-dihydroquinolines, and more fully reduced derivatives, such as l,2,3,4-tetrahydroquinolines, are included. The compounds of this invention are represented by the following formulas:

wherein R is acyl having from 1 through 4 carbon atoms; R R and R are alkyl having from 1 through 4 carbon atoms; R, is hydrogen or alkyl having from 1 through 4 carbon atoms; R is hydrogen, halogen; alkyl or alkoxy having from 1 through 4 carbon atoms, or lower aromatic; and R is alkyl or alkoxy having from 1 through 4 carbon atoms, or monocyclic aromatic.

In the interest of clarity and convenience, the sub stituents are numbered in accordance with the most common numbering system for quinolines as shown in The Ring Index, 2d ed. by Patterson, Capell and Walker, published and copyrighted by the American Chemical Society (1960).

The preferred compounds of this invention are those in which the acyl group on the l-position is halogenated with from 1 through 4 halogen atoms and R is hydrogen. The invention includes, however, many compounds with various other R entities; for example, ethoxy, tertbutyl, benzyloxy and chloro. Furthermore, the preferred compounds of this invention have chlorine substituents "ice in the acyl group and R is lower alkyl. 2,2,4',8-tetramethyl compounds are preferred because they are particularly elfective, and those in which R R and R or R are methyl are the most readily accessible.

In accordance with this invention, it has now been found that the new compounds of this invention are very effective pre-emergent herbicides; that is, they are most useful when applied to the soil after the crop seed is sown, but before the plants emerge. These compounds are particularly effective when it is desired to remove weed grasses from a broadleaf crop situs; this invention includes such a process.

The present compounds can be formulated into their liquid or solid herbicidal composition and in [both forms a surface-active agent can be used to improve stability and facilitate application. They are soluble in a wide range of organic solvents, such as alcohols, ketones, hydrocarbons, halogenated hydrocarbons, and the like, and an appropriate non-ionic surface-active agent may be present in such solutions. The new compounds can also be suspended or emulsified in suitable liquid media, usually aqueous, and stabilization may be achieved with either ionic or non-ionic surface-active agents. Other conventional adjuvants can be employed in the formation of compositions of the present invention. Also, the novel hydroquinolines can be used alone or in combination with other herbicides and pesticides.

The concentration of the herbicide in the composition can vary widely and depends primarily on the intended use. For direct application, at least 1% by weight of composition is preferred, but amounts of about 10%, 25% or 50% by weight of composition can be used, particularly if subsequent dilution is intended. The amount of active ingredient applied per acre can be from about 2 to about 25 pounds, but the preferred application rate is from about 4 to about 6 pounds active compound per acre.

These new compounds are readily produced by the acylation of a hydroquinoline analogous to the product desired, the preferred acylating agents being acyl halides, particularly the acyl chlorides, although acyl anhydrides can also be used. The acylation is preferably carried out in the presence of an acid acceptor, such as a tertiary amine, and most conveniently in the presence of an inert solvent, including hydrocarbons, halohydrocarbons, ethers and the like. The acylation can be carried out at temperatures from room temperature to about C.

The starting material for the compounds in which R is phenoxy is o-aminodiphenylether (See Ullmann, Ber.; 1896, 21, 1881 and Jones and Cook, J. Amer. Chem Soc. 1916, 381540.) This is condensed with acetone (according to the well known procedure exemplified by page 641 of Chemistry of Carbon Compounds, vol. 4, Part A, by E. H. Rodd and published by Elservier Publishing Co., 1957) to give 2,2,4-trimethyl-8-phenoxy-1,2-dihydroquinoline which through hydrogenation gives 2,2,4-trimethyl-8-phenoxy-1,2,3,4-tetrahydroquinoline The starting material for the compounds in which R is phenyl is o-aminodiphenyl (See J. Chem. Soc.; 1927,91). This is condensed with acetone (see above) to give 2,2,4-trimethyl-8-phenyl-1,Z-dihydroquinoline which through hydrogenation gives 2,2,4-trimethyl- 8-phenyl-1,2,3,4-tetrahydroquinoline. Other compounds can be obtained by substituting other ketones for acetone in the foregoing reaction.

Specific examples of the new herbicidal hydroquinoline derivatives are:

1-acetyl-2,2,4,S-tetramethyl-1,2-dihydroquinoline; 1-chloroacetyl-2-2,4,S-tetramethyl-l,Z-dihydroquinoline; 1-bromoacetyl-2,2,4,S-tetramethyl-1,2-dihydroquinoline;

EXAMPLE 1 This example described the production of the new compound 1-chloroacetyl2,2,4,8-tetramethyl-1,2-dihydroquinoline.

A solution of 9.35 grams of 2,2,4,8-tetramethyl-1,2- dihydroquinoline and 7.4 grams of diethylaniline in 75 cc. of benzene was added during minutes to a stirred solution of 4 cc. of chloroacetyl chloride in cc. of benzene. The solution was allowed to stand at room temperature for four days and Was then filtered to remove crystals of diethylaniline hydrochloride.

Evaporation of the benzene from the filtrate gave 1- chloroacetyl-2,2,4,8-tetramethyl-1,2-dihydroquinoline as an oil in practically quantitative yield.

EXAMPLE 2 This example illustrates the herbicidal action of the product described in Example 1.

In the test used to assess the effectiveness of the material as a pre-emergent herbicide, needs of several species of grasses, including rye grass, wild oat, brome grass, sorghum, foxtail, barnyard and crab grass, and of several species of broadleaved plants, including radish, sugar beet, cotton and tomato were sown in green-house boxes.

' After sowing, the surface of the soil in the boxes was sprayed with an aqueous dispersion of the material to be tested at a rate equivalent to 5 pounds of the active compound per acre. Observation on normal or abnormal seedling growth or seedling failure was usbsequently carried out.

On the results of this test, the material was rated as moderately toxic to grasses generally with severe toxicity to rye grass, foxtail, barnyard, crab grass and sorghum, and as having no toxic action on broad-leaved species.

What is claimed is:

1. A compound of the formula wherein R is a haloalkyl carbonyl the alkyl of which totals 1 through 3 carbon atoms said haloalkyl being substituted by from 1 to 3 like halogen atoms on at least one of the alpha and beta carbon atoms; R R and R are primary and secondary alkyl of 1 through 4 carbon atoms; R is hydrogen or primary or secondary alkyl of 1 through 4 carbon atoms; R is hydrogen, halogen, alkyl or alkoxy of 1 through 4 carbon atoms, phenyl or phenoxy, R is alkyl or alkoxy of 1 through 4 carbon atoms, phenyl, or phenoxy.

2. A compound according to claim 1 in which R has 1 or 2 halogens.

3. A compound according to claim 1, wherein in R the halogen of said haloalkyl carbonyl is chlorine.

4. A compound according to claim 1, wherein R is chloroacetyl or dichloroacetyl.

5. A compound according to claim 1, wherein R R R and R are methyl.

6. A compound according to claim 1, wherein R is alkyl of 1 through 4 carbon atoms. the halogen of said haloalkyl carbonyl is chlorine.

7. A compound according to claim 1, wherein R is alkyl of from 1 through 4 carbon atoms.

8. A compound according to claim 1, wherein R R R and R are methyl, R is alkyl of 1 through 4 carbon atoms.

9. 1-chloroacetyl-2,2,4,8-tetrarnethyl-1,2-dihydroquinoline.

References Cited UNITED STATES PATENTS 2,268,419 12/1941 Paul 260283 X 2,661,276 12/1953 Schlesinger et al. 260283 X 2,661,277 12/1953 Mowry et al 260283 X 2,857,387 10/1958 Beaver et al. 26O287 2,864,682 12/1958 Speziale 71/2.5 3,149,117 9/1964 Brown 260283 3,223,708 12/1965 Mod 260287 3,255,247 6/1966 Olin 7l2.5 X 3,275,628 9/1966 Brown 260-287 X 3,438,993 4/1969 Wilbert 260289 X OTHER REFERENCES Japan 492 (1964) January 1964, Fujimura et al., Abstracted in Chem. Abstr., vol. 60, C01. 11994 (1964).

D. G. DAUS, Primary Examiner U.S. Cl. X.R. 

